The present disclosure relates generally to powered, fastener-driving tools, wherein the tools may be electrically powered, pneumatically powered, combustion powered, or powder activated, and more particularly to a lockout mechanism for a fastener-driving tool that prevents actuation of the tool when there are no fasteners remaining in a collation in the tool magazine.
Powered, fastener-driving tools, of the type used to drive various fasteners, such as, for example, staples, nails, and the like, typically include a housing, a power source, a supply of fasteners held in a collation, a trigger mechanism for initiating the actuation of the tool, and a workpiece-contact element (also referred to herein as a “workpiece contacting-element” or “WCE”). The workpiece-contact element is configured for engaging or contacting a workpiece, and is operatively connected to the trigger mechanism. When the workpiece-contacting element is in contact with the workpiece, and depressed or moved inwardly a predetermined amount with respect to the tool housing, as a result of the tool being pressed against or moved toward the workpiece a predetermined amount, the trigger mechanism will be enabled to initiate fastener driving. Upon actuation of the tool, a piston including a driver blade is driven through a cylinder in the housing and into a drive channel loaded with a fastener. The driver blade contacts and drives the fastener into the workpiece.
Many fastener-driving tools include depth of drive adjustment mechanisms that adjust the depth in which the fasteners are driven into the workpiece. For example, fasteners may be driven into a workpiece so that the heads of the fasteners are flush with the outer surface of the workpiece. Alternatively, the depth of drive mechanism is adjustable so that the fasteners are recessed or driven to a designated distance in the workpiece and the heads of the fasteners are a designated distance below the outer surface of the workpiece. Recessing the fasteners is preferred in some circumstances, such as when attaching drywall to wood studs or other supports, so that the fastener heads can be covered and hidden with a drywall patching or joint compound, or other suitable setting compound.
On a job site, it is often difficult to tell when the fastener magazine is empty or near empty. Typically, a user finds out that the tool magazine is empty when the tool is “dry fired,” i.e., actuated without a fastener loaded in the fastener drive channel. This is particularly a problem when attaching drywall, because the driver blade extends outwardly from the end of the workpiece contact element to recess the fasteners in the drywall, and thereby makes a mark or hole in the drywall when the tool is dry-fired. As a result, extra time and materials are needed to repair the inadvertent holes and damage to the drywall.
Accordingly, there is a need for a fastener-driving tool designed to prevent actuation of the tool when there are no fasteners remaining in the magazine.